My Hero Z Kai
by Bionic-TitanX
Summary: Goku and Chi Chi gave birth to two boys. One named Gohan. The other Izuku. Life was peaceful for the two until the arrival of Goku's brother speaking on his Saiyan heritage. Now several new dangers have been revealed and it is the job of Goku, his sons, and the rest of the Z fighters to protect the Earth from harm whether it be from aliens, androids, or Quirk users.
1. Chapter 1

A/N: Alright. So I've been trying to figure out an interesting unique Dragon Ball and My Hero crossover fic for a while now. I tried writing a story where you see Gohan after the Cell Games in My Hero Academia, but it was terribly boring. I think I figured out an interesting one now.

Two boys were born in age 757. Both of them were born with tails. The older of the two, named Gohan, had spiky black hair and was born in May. The younger of the two brothers was born in July with curly black hair. The most noticeable thing about the two brothers was that both of them had green highlights and the younger brother, named Izuku, had freckles on his face. The two were born to a beautiful couple. A man by the name of Son Goku and a woman by the name of Chichi.

4 years have passed since their birth and they grew up with quite an appetite devouring their dome shaped house. They had the same appetite as their father who would eat the same amount as 8 fully grown men.

Today was going to be a reunion for Goku with his friends that he made in the past. He couldn't wait to see all of them again and introduce them to his kids! His pride and joy!

"Nimbus!" Goku called out.

All of a sudden, a golden cloud appeared from out of the sky flying over to Goku. He stepped on it and brought his two children along with him. While he was standing on the cloud, the two children were grabbing onto his legs looking at their father in amazement. Goku looked down at his children with a bright smile on his face before looking back up with a certain destination in mind.

*Line*

A bald man with sunglasses, gray beard, tropical shirt, and cargo shorts was sitting down on a chair near his house, painted pink, that was located on a small island. His pet turtle was right next to him and the geezer was sipping on some milk from a coconut.

"It's been pretty boring these past few years hasn't it Turtle?" The old man asked.

"Yeah. You could say so, but I prefer the word peaceful." Turtle responded.

The old man hummed and continued sipping his drink until he saw something fly towards him and it looked relatively big. Being the old man he was, he spat out his drink and quickly got up seeing how it was fast approaching him.

"Roshi. What's the matter?" Turtle inquired.

"Something big is flying towards us!"

Turtle looked up to see what Roshi was talking about and was alarmed as well seeing a flying contraption flying towards them seemingly about to crash. Turtle tried to speed away, but it wasn't really working all that way for Turtle. Thankfully, at the last moment, the flying contraption slowed down and moved to land over to the part of the island where there was more space. Roshi and Turtle breathed a sigh of relief knowing the plane didn't crash into them. A blue haired woman came out of the plane with a smile on her face. She looked rather youthful as well.

"Hey Roshi! Turtle! Long time no see!" She waved.

Roshi was going to scream at the young woman for almost giving him a heart attack, but stopped when he noticed her features. Specifically her, ahem, melons.

"Oh! Why yes it has Bulma and I see you've grown well. Very healthy."

Before he could try anything, a bald monk flew in and bopped Roshi on the head.

"Oh, my bad. Sorry Master Roshi."

Master Roshi was now clutching his head in slight pain.

"Watch where you're landing Krillin!" He yelled.

Krillin just looked at him with a smile on his face and turned to look at Bulma.

"Bulma! It's been so long since I last saw you!"

"Yeah. I figured I'd come and visit considering how long it's been."

Krillin nodded still smiling and hugged her.

"So what's been happening these past 5 years for you Krillin?"

Krillin shrugged.

"I just stayed with Roshi for the past couple of years. How about-"

Before Krillin could finish, a blonde haired man with two strands of hair sticking out to form a V landed on the island as well laughing.

"Well, if it isn't the big shot himself." Bulma commented with her hands on her hips.

The blonde stood tall at 7 feet and 2 inches. He wore cargo pants and a white t-shirt. He was youthful looking and had a nice tan compared to Bulma and Krillin's more pale appearances.

"Ha! Well, someone's gotta give the world a symbol to look up to and I don't see anyone else willing to take up the challenge."

"Toshinori, not all of us wanted to be heroes as bad as you did." Krillin pointed out.

"And not everyone has that natural charisma like you and Goku." Roshi commented.

Toshinori rubbed the back of his head still with a smile on his face, but he was feeling slightly embarrassed.

"Well, I came for a family reunion, but it seems like you're all here to call me out for my actions."

"Oh, please! Like you'd get such royal treatment." Bulma retorted folding her arms, but she smiled nonetheless. "But still, it's nice to see you again Yagi."

Toshinori blushed a little bit and tried to cover it.

"Oh, look. The big man's blushing!" Turtle called out.

The group laughed at Toshinori's expense until a cloud soaring across the sky slowed down and landed in the middle of the group.

"Hey guys!"

Everyone was now especially surprised to see the spiky haired man known as Goku.

"I can't believe it! It's really Goku!" Turtle exclaimed.

After the exclamation by Turtle, everyone began to gather around Goku until Bulma noticed two children holding onto Goku's legs and she kneeled down to notice them better.

"Aww. Who are these little cuties?" Bulma asked looking up at Goku.

Everyone all of a sudden noticed the little ones. Krillin sighed.

"Oh boy. Did Goku just kidnap some children?" Krillin facepalmed.

"Goku, this is a serious crime you committed." Toshinori reprimanded.

Goku just laughed throughout it all.

"No. No. They are actually my kids."

This was an eye opener for everyone.

"Wow. I didn't know that you had it in you Goku." Krillin spoke.

"Out of all of us, I wasn't expecting for you of all people to start having children first." Bulma mentioned.

"Well then, do you plan on making them martial artists like us or even Toshinori?" Master Roshi questioned.

"Unfortunately no. Chichi wants them to become scholars."

"Seriously? Does she not know who the father of these kids are?" Krillin questioned.

Goku simply shrugged.

With the friends enjoying their reunion with each other, no one was prepared for what happened next. Most of the friends' eyes widened due to the sensation they were feeling. The ki they were feeling was intense compared to their own. It was on a whole other level!

"T-That ki!" Krillin exclaimed.

"It's overwhelming!" Toshinori spoke.

A man with long spiky hair wearing a strange suit of armor floated down from the sky with his arms crossed. He had a bushy belt wrapped around his waist. He had a look of disappointment on his face.

"Life is plentiful on this planet. What happened to your mission Kakarot?!" The odd looking man yelled.

Everyone looked at the man in confusion as he began to walk towards Goku. Who was this Kakarot?

"Have you forgotten your mission Kakarot?"

Everyone soon began to realize that this man was talking to Goku.

"I'm sorry, but who are you?" Goku asked.

The long haired fellow growled.

"Come on Kakarot! You're telling me that you don't remember your own big brother? Are you gonna tell me next that you don't even remember that you are part of the Saiyan race?"

"Um. About that." Goku scratched the back of his head.

This was when Master Roshi spoke.

"Goku, I think this man is telling the truth here."

Krillin, Toshinori, and Goku were gawking.

"I have a brother? But how?" Goku pondered.

"Allow me to explain Goku. You see, your grandfather found a strange space capsule in the woods one night. There was a baby with spiky hair and a tail in that space pod. As you already probably figured out, that baby was you Goku. You were a terrible baby at first. You were so ill-tempered and violent all the time. You would throw tantrums on the daily. One day, while Gohan was trying to carry you, you kept moving trying to get out of the basket. Once you did, he tried to get a good grip on you, but he couldn't. You ended up falling down a ravine and hit your head causing you to suffer a severe head trauma. You were lucky enough to be alive and the hit to your head seemed to have you changed you for the better as from then on, you were a well-behaved kid."

Goku was beyond shocked hearing Roshi's recollection of events revolving around him and how he came to become the man he is today. If what Master Roshi was saying was true, then that'd really mean he wasn't human after all and that the man in front of them was his brother after all. But, that's impossible! Before Goku managed to process all of this new information, his supposed brother spoke up after sighing in frustration.

"I see. I suppose that makes sense as to why you haven't eradicated all life on this backwards planet yet. That head trauma caused you to forget all about your Saiyan heritage. Then again, I suppose it was a good thing you didn't kill them all off considering Lord Frieza has shown a bit of an interest in the Earthlings due to the unique abilities many of them have. At the very least, you could have enslaved the population!"

No one liked what the supposed brother of Goku was saying right now. Enslaving the human population? Killing off the human population? How was this man Goku's older brother? Just by what he was saying, that already told them enough about the man. He was no good.

"We are some of the few only known surviving Saiyans left. Our home planet was destroyed twenty years ago and including yourself and I, there are only 4 known Saiyans who are still alive. There's a possibility there are more, but it's yet to be confirmed. We'll deal with the Earthlings later. Currently, I need your help in eradicating all life on another planet that Lord Frieza finds quite valuable and the enemies are surprisingly strong there as well."

Goku was even more shocked at the fact his own brother was asking him to partake in killing off a whole race and for what? To please some freezer? Was he insane?

"Absolutely not! Are you crazy? You claim you're my brother and expect me to help you kill off a whole species and for what? To please a refrigerator? How dare you! I don't even know your name!" Goku yelled in response.

The elder of the two growled in response. He tightened his fists and glared at Goku until his eyes drifted spotting the two children hiding behind Goku's legs. He smirked.

"What's this? Two children hiding behind their father's legs? Well then, if you won't go with me, I guess I'll take my nephews with me and bring them to space so we can have some 'quality' time together. If you want to see them again you'll have to either kill one hundred of these humans or capture one hundred of them so we can bring them to Lord Frieza and have him sell them. Do either of these two within the next 24 hours or say goodbye to your kids!"

After saying his piece, Goku shifted his body into a more defensive position.

"Stay behind me Gohan. Izuku." Goku spoke to the kids.

"Ha! What? Is this some stance you've learned during your time on this planet? Well little brother, allow me, Raditz, to show you just how big of a difference we are in power!"

Raditz launched himself at Goku. Goku tried to defend himself against Raditz, but Raditz was simply too fast for him. He was stronger and faster than him by a large margin. He kneed Goku in the stomach and grabbed the two children from behind. Raditz then kicked Goku in the face launching him back several feet. The two kids were crying in Raditz's grip.

"If you don't do as I said, these two will die!" Raditz yelled.

Raditz flew off with the two children being held by the collar to a far distance away from Kame House. Once Goku managed to finally force himself up from the ground, he rubbed his head in frustration. He wasn't even focusing on the pain he was feeling right now. Instead, Goku was thinking about a plan to get back his children. He refused to kill anyone.

"Goku." Toshinori spoke. "This man is strong. Stronger than anyone we've faced before. You won't be able to defeat him by yourself so I'll come with you in order to find your brother and rescue your kids."

"Same here! You're going to need all the help you can get this time around Goku!" Krillin announced.

Goku sighed.

"Thanks guys, but Raditz is incredibly strong and seems to be quite ruthless. I don't want either of you two to get involved. Krillin, you've died before. If you were to die again, Shenron can't bring you back and Toshinori, I can't afford for you to die either. The people look up to you and the world needs you. You can't die from so early on. I'll handle this alone."

Before Goku lifted himself off the ground someone else appeared.

"Wait."

Goku turned and his eyes widened to see who it was.

A/N: High school has started and I'm tired. I know that this is just about the same as the original, but the further in the arcs we go, the more you see it differentiates from the manga and more you see My Hero characters get involved in the story alongside the stories of the two franchises getting fused. I'm tired and hungry so bye!


	2. Life or Death

A/N: FYI, all my stories will probably take months to update until Winter and Summer break. Because high school. Onto the story!

A green, muscular man with antennas on his forehead was floating in the air staring down at Goku. He had his arms folded and wore a purple gi.

He floated down to the ground and began to walk over to Goku and the others. Everyone tensed and got into their fighting stances. The green man sighed.

"I'm not here to fight you. Instead, I have an offer."

Goku raised an eyebrow to this.

"That man who just left. I encountered him earlier. His power. It was completely overwhelming. It was unlike anything I've felt before. I stood no chance against him and from the looks of it, neither could you. That's why I have this proposition for you Goku. Let's work together this time around. We have a common foe and if we could work together for once, our chances of being able to take him down will be greatened."

Goku was skeptical about this considering Piccolo could betray him at any moment, but he needed to get his sons back. Who knew what Raditz would do to his kids if he didn't save them as fast as possible? He didn't have much choice in the matter either. Against his better judgement, Goku agreed to work with Piccolo.

"What's your plan to defeat Raditz?"

"Well, there was this move I created and planned on using on you, but it's going to have to be used on an even greater foe today. It's a powerful attack, but the only problem with it is that it takes time to charge. The more time it charges, the more powerful it can become. Powerful enough to even hurt your 'brother."

"So, what do you want me to do?"

"Distract him while I charge up the attack. Wear him down a bit. Make sure to keep him pinned so I can shoot him with the Ki attack. It's one blast and neither one of us can afford to miss the shot."

Goku nodded before turning to Bulma.

"Bulma. Do you happen to have your Dragon Radar with you? We could use it to track down Gohan since he has the 4-star Dragon ball attached to his hat."

Bulma nodded and handed him the radar. She always had it on her for safekeeping and in case of emergencies like this or when enemies would also be searching for the seven spheres.

"Thanks Bulma. Piccolo. Let's go save my sons." Goku exclaimed.

Piccolo tch'ed before flying off with Goku to find Raditz. When they finally found his location, Raditz only seemed to have a smirk on his face. From the corner of Goku's eye, he noticed someone banging on the inside of a space pod. Wait. There were four hands banging. Goku's eyes widened. Raditz trapped his kids in the space pod.

"So, tell me Kakarot. Did you do as I asked and enslave all of those humans so soon or do you plan to come with me?"

"I'm not going anywhere Raditz. I'm here to retrieve my kids and put a stop to you before you hurt anyone."

"Oh? And do you honestly think that you're strong enough to face off against me the way you are now? As for you Namekian." Raditz pointed to Piccolo. "What are you doing here on this barely useful planet and so far away from home?"

Piccolo raised an eyebrow at this. What was a Namekian and why was he calling him that? Was it possible that there were more like him out there? He'd have to find out more about that later. Currently, he had to get rid of this invader.

Both Goku and Piccolo began to take off their weighted clothing so that they could fight better and so they were stronger than the last time. They had to give it everything they had. It was now or never.

Raditz questioned what they were doing at first until his scouter began to pick up a change in their power levels. He was shocked to see this.

"Stripping makes you stronger on this planet?" He questioned aloud.

Everyone just paused for a second after hearing Raditz's question before a bead of sweat began to form on the adversaries of Raditz' foreheads.

"We were wearing weighted gi." Goku quickly explained to get past the awkwardness.

"Oh. That makes much more sense."

They resumed the seriousness of the situation and Goku launched at Raditz going for a jab to the face that was quickly blocked. Raditz went in for a punch to the gut, but Goku managed to dodge and backflip attempting to kick him in the back of the head, but Goku was too slow. Raditz grabbed his foot and yanked him. He threw Goku down to the ground leaving a crater, but Goku rose back up. Raditz kicked Goku back down though. Goku grunted in pain as Raditz kicked him in the ribs. He grabbed his foot and pulled him down as well. He pushed himself back up and was panting.

Before Goku could do anything else, Raditz threw a jab at Goku's leg causing his legs to buckle up. Raditz threw a quick Ki attack at Goku and managed to damage Goku severely.

"That wasn't even one of my named attacks and look at how badly it's injured you Kakarot. Face it. You're weak and you stand no chance against me."

Goku was kneeling down on the ground looking as if a bomb was just set off on him. Raditz saw Goku whisper something. He gritted his teeth seeing this as a sign of disrespect. He grabbed Goku by the hair and forced him to look him directly in the eye.

"What'd you say?"

"I said 'Kame-"

A bright blue form of energy began to form in Goku's cupped hands. Raditz' scouter began to pick up on it as his little brother's power level began to rise. This didn't look good.

"Hame-"

Raditz let go of Goku and fled into the sky to charge his own attack.

"Double Sunday!"

"Ha!"

The two attacks began to collide. For a moment, the two energy attacks seemed to be at a standstill, but Raditz began to win in the power struggle. Goku exerted more energy into his attack, but Raditz' power was just too overwhelming for Goku and he was hit by the attack.

Raditz smirked seeing how pathetic his little brother was. His smirk turned into a frown as he saw his little brother begin to get back up. He was a resilient one. He'd give him that.

"Well. I'm impressed with how you could concentrate your power into that single Ki attack, but even that isn't enough to stop me."

Goku chuckled lightly at this leaving Raditz in a confused state.

"I wasn't aiming to defeat you with that attack. It was just a distraction.

"A distraction? For what?"

A moment of realization hit Raditz. He forgot about the Namekian that was with Kakarot. He quickly turned his head around only for.

"Special Beam Cannon!" Piccolo yelled.

Raditz tried to sidestep the attack, but he exerted himself a little too much in the Ki clash with Kakarot and was too slow to completely dodge the attack. It hit him in his chest, but nowhere fatal. Raditz felt the attack pierce right through the armor and blood splattered out of his mouth. He growled at the pain, but he forced himself to still stand and fight. He wouldn't get bested by such weaklings.

"Fools. You think such an attack would defeat-Gahhh!"

Goku grabbed Raditz's tail. He remembered what would happen when someone grabbed his tail. He would become incredibly weak and he assumed it would be the same for Raditz. Sure enough, his thought process worked.

"Piccolo! I've got him pinned down! Charge up another one of those attacks!" Goku yelled in desperation.

Raditz was panicking. He was bested by his own little brother and was going to die to such weaklings. No. He refused to die here! He had to think quick.

"Kakarot. Look. I'm sorry for kidnapping your sons."

Goku wasn't listening.

"I know you hate me for what I've done and I don't blame you for it either. I would hate myself if I were in your position as well, but I was desperate. The Saiyan race is nearing extinction and we need as many of us to survive. It's bad enough there aren't even any female Saiyans alive anymore, but now you're going to kill your own brother? How would you think mother and father have reacted?"

"I...never knew my parents." Goku spoke somberly.

"I could tell you all about the Saiyan race. You and your kids. I could even inform you about your race Namekian!" Raditz pleaded. "Allow me to live and I'll tell you everything. Even about the other surviving Saiyans who are far stronger than me!"

Goku looked to Piccolo.

"What do you think Piccolo?"

Piccolo sighed and lowered down his two fingers from his forehead deactivating his Special Beam Cannon.

"It seems like your brother has some valuable information. I say we should keep him alive. Especially with the fact that there are others out there who are even stronger than him. We could learn how to defeat them and prepare for them whatever time they come."

"Y-You see this scouter on my head? Well, it also works as a transmitter. There are two even stronger Saiyans and they'll arrive here in a year's time in order to take over the planet and enslave the human race due to their unique abilities."

After hearing this, Goku snatched the scouter from Raditz and crushed it in his hand.

"We'll let you live, but we can't afford for you to keep your tail."

Hearing the part about allowing him to leave relieved Raditz, but the tail part unnerved him. His eyes widened and tears began to shed from Raditz's eyes as he could feel his tail being ripped off. Raditz was screaming in pain, but was powerless to do anything. After his tail was ripped off, Raditz was left disoriented. He was far too weakened from being hit by that other Ki blast. It wasn't enough to kill him in an instant, but he needed medical treatment and soon!

Goku left to free his sons from the space pod and he was relieved to see the two relatively left unharmed.

"Let's get you two back home."

Goku called the Flying Nimbus over and sent the two on their way home using the flying golden cloud. Then, he turned back to Raditz and Piccolo. He grabbed Raditz by the hair.

"As for you, you have some valuable information. That's the only reason we're letting you live. Bulma could find your tech useful. We'll make sure you won't die, but we're going to have some restraints on you until we can truly trust you."

Raditz nodded and grunted in pain.

"Yes Yes! I'll tell you everything!"

"Maybe your information on top of your tech could help Bulma make some things useful enough to make more effective training for the arrival of the other Saiyans you mentioned."

A/N: So yeah. I didn't off Raditz like in the original story. I have plans for Goku and King Kai. Same for Piccolo and the kids. Raditz will be useful for this story. Since this story takes place before most of the events in My Hero Academia, how would you like for me to introduce some of the characters? As you already know, we have All Might in this story, but he hasn't done much...yet. Tell me what you think I should do about these characters. Someone like one of the pro heroes I can maybe have learn Ki and be someone to help during the time when the Saiyans arrive. Sort of help as someone to defend Earth. Maybe even with the inclusion of someone like Endeavor, I can even introduce Shoto into the story much earlier. Tell me your thoughts in the reviews. Besides that, I have a project to work on so Bionic-TitanX out!


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